Green pigment composition



April 25, 1950 M. scALERA ET AL 2,505,744

GREEN PIGMENT COMPOSITION Filed March 7, 1946 ATTO RN EY UNITED STATES rATsNT OFFIC GREEN PIGMENT COMPOSITION Mario Scalera and Robert E. Brouillard, Somerville, N. J., assgnors to American Cyanamid Company, New York, N. Y., a corporation of Maine Application March 7, 1946, Serial No. 652,705

This invention relates to green pigment compositions which are blends of chemically dissimilar blue and yellow organic pigments. The new compositions possess outstanding brilliance and color stability. 5 why this unusual result is obtained and the pres- In the past the problem of obtaining green ent invention is not intended to be limited to pigments has been a serious one. The green pigany yparticular theory of action. ments known to the art suffer from one or more That the blending of phthalocyanine pigments deficiencies. They are either expensive, dull and with the particular alpha acylamino anthraunattractive, have poor permanence to light or l quinones gives such surprisingly brilliant and atmospheric contaminants prevalent particularly strong pigments is contrary to the general exin seaboard and industrial areas, or have a xed perience of blending yellow vat dyes with phthalshade which cannot be changed to a different ocyanines. Thus, for example, when phthalocyahue Without impairing brilliance. nines are blended with 1,2,5,6-anthraquinone-C- The green pigments now commercially availl diphenyl dithiazole the resulting pigment, while able comprise Chrome Green, Chromium Oxide, green, exhibits inferior properties of color and Hydrated Chromium Oxide, highly chlorinated stability. Similarly, when the phthalocyanine is copper phthalocyanine and complex acid salts of blended with the bright yellow vat pigment green triphenylmethane dyes. 2.4,8,9dibenzpyrene quinone dull green pigments The triphenylmethane pigments are too fugiof very inferior stability result. The production tive for any outdoor use, while the highly chlorof bright green blends with phthalocyanines apinated phthalocyanines are too expensive for use pears to be a unique characteristic of the alpha in tones deeper than a tint. Therefore the bulk acylamino anthraquinones. The reasons why of the green pigment market, particularly for the improved results are obtained only with these paints, lacquers and durable inks, has been particular yellow dyes are not known, and the shared by Chrome Green and the Chromium invention is not intended to be limited to any oxides. theory of action. Chrome Green darkens on exposure to light It is an advantage of the present invention and thus fades off-shade. Furthermore, its rethat the blending of the blue or greenish blue sistance to both acid and alkali is poor, its shade phthalocyanines with a yellow alpha acylamino changing to dull yellow or blue under these anthraquinone may be effected by Various methagencies. Hydrated Chromium Oxide, which has ods and presents no critical problem. Thus, for better fastness, is deficient in tinctorial strength example, dry blending may be used which is and grinding characteristics. cheap and simple, but we prefer a wet blending U Green pigments have been prepared by blendof pre-conditioned pigments, for example, by acid ing copper phthalocyanine pigments and yellow pasting in sulfuric acid and coprecipitation in azo pigments of the Hansa Yellow class. Such water. The coprecipitation produces vyellower combinations are an improvement over some of products which permits obtaining the same shade the green pigments previously known to the art. with reduced amount of the yellow pigment. As They are, however, decient in brilliance and of the alpha acylamino anthraquinones are in genl only moderate color stability. Dichlorobenzidine eral more expensive, this method permits some Yellow (3,3 dichlorobenzidineeacetoacetanil saving in cost. 0n the other hand, dry blending ide) may also be blended with copper phthalocyor ordinary wet blending gives shades which are anine to give green pigments comparable to those bluer and somewhat stronger. obtained with the Hansa Yellows. The term pigment strength is used throughout According to the present invention blue or this specication to refer to the tinting strength greenish blue phthalocyanine pigments are of the products when they are employed. as pigblended with yellow pigments obtained by subments in coating compositions. If a colored pigstituting the amino group of alpha amino anment shows a high pigment strength after it has thraquinone by the radical of an aromatic ca-rbeen blended with white pigment, then it can boxylic acid such as benzoic acid. These blends also be said to have a high tinting strength. The are brilliant green pigments of variable hue, exdetermination of pigment strength may be efcellent strength and stability to light and various fected in various ways, for example, by a tristimatmospheric contaminants. The blended pigulus method adopted by the International Comments of the present invention not only show mission of Illumination and described in the 10 Claims. (Cl. 10G-288) excellent color strength and stability characteristics but they also exhibit a strength which is greater than that calculable from the individual pigment components themselves. It is not known Journal of the Optical Society of America, vol, 23, page 359. In this method tristimulus luminous reectance is a measure of strength. The higher the luminous reflectance the less the absorption of the pigment, and therefore the lower its strength. Another method is the Munsell system (Journal of Optical Society of America, vol. 33, page 385). In Munsell units a smaller value represents a stronger pigment.

It is possible both by the tristimulus and the Munsell method to calculate on the basis .of the individual components what the strength of a blend should be. It is also possible lby the use of spectrophotometric curves drawn on a recording flickering beam spectrophotometer provided with cams permitting the production of shape invariant with concentration to l determine the theoretical strength of blends graphically. The comparison of predicted and actual blend strengths will be described in more detail in conjunction with the drawing, which shows spectrophotometric curves of copper phthalocyanine sindA of 1-(2hydroxybenzoylamino) anthraquinone, predicted curve for a blend of 25% o the rst, pigment and 7,5% or" Vthe second, and an actual .curve of the same blend, lal1 curves .being taken on Zinc oxide reductions made from the base vinks of the respective pigments by conventional methods.

fIfhe following table illustrates the great in. crease in strength of the blends of the present invention as compared with predicted strength. Data is given both. in tristimulus luminous reiectance Values and Munsell units.

It will be apparent that considerably greater strength is obtained in the blends or the present invention than would be predicted from` a color analysis of the components. The increased strength may be interpreted in terms of eiective amounts of pigments. Thus, for example, when the 'Z5-,25% blend is compared With the predicted value its effective strength is equivalent to that which would be predicted for 85 parts orthe yellow pigment and 38 parts of the blue pigment, representing an increase in eiiciency of V13% for thel yellow and 38% for the blue.

The surprising increase in strength is obtained Without sacrincing other desirable characteristics. In fact, the blend also has other improved characteristics, particularly as respects grinding characteristics. It is well known that copper phthaiocyanine is a hard pigment which dispersos only with.` difficulty in organic vehicles and requires dispersing agents. The blend with the alpha acylamino anthraquinone is a soft pigment which will disperse easily in organic vehicles without any. dispersing agent. It is not known why. the anthraquinone compound should so greatly influence the physical form of the phthalocyanine and notheoretical explanation is intended to limit the Ascope of the present invention.

While it is an advantage of the present inyenv tion that the soft blend may be dispersed in organic, vehicles without using a dispersing agent, the .invention of course, not limited thereto,

and on the contrary, if desired, dispersing agents may be used.

Among the alpha acylamino anthraquinones useful in blends of the present invention may be mentioned the following: 1-(2hydroxybenzoyl amino) anthraquinone, 1(2nitrobenzoylamino) anthraquinone, -l-(lnitrobenzoylamino) anthraquinone, 1-(2-chlorobenzoylamino) anthraquinone, l-(4ch1orobenzoylamino) anthraquinone, 1-(3,4'-dichlorobenzoylaminm anthraquinone, 1-(uroylamino) anthraquinone. It is also possible to use alpha acylamino anthraqui- Vnones in which there is a substituent on the anthraquinone rings so long as this is a non-auxechromic group. Thus, for example, l-benzoylamino-G-chloroa-nthraquinone or l-benzoylamino.5nitro anthraquinone may be used. Other aroyl derivatives'of alpha amino anthraquinone have also been found useful. These are naphthoyl, anthroyl, and derivatives of diand polycarboxylic acids of the aromatic series, such as isophthalic acid di-(alpha-anthraquinonyl) amide, terephthalic acid die(alpha-anthraquinonyl amide, p,pdiphenyl dicarboxylic acid di-(alpha-V anthraquinonyl) amide, trimesic acid tri-(alphaanthraquinonyl) amide and the like.

The above compounds may be easily prepared by heating the .alpha amino anthraqurlone and the `corresponding Iaromatic acid chloride inv an inert solvent.

It is possible .to use commercially available acylamino anthraquinones and they need not be pre pared from highly puried alpha amino anthraquinones. However, maximum brilliance is obtained when highly pure alpha amino anthraquinone is used in the production of the acylamino lanthraquinones. ,Such highly purified alpha amino anthraquinones may be prepared, forV instance, from phthalimido anthraquinones, by methods known to the art.

Among the blue to green phthalocyanines (tetrabenzo tetrazaporphinesf) .copper phthalocyanine is the most common and is preferred. However, other metal phthalocyanines, such as nickel, cobalt, Zinc, etc., may be used', as can metal freeA phthalocyanine, as well as the nuclear halogen substitution products of the p-hthalocyanines.

The invention will be described in greater detail in conjunction with the following examples. The parts are by weight.

EXAMPLE 1 One part of copper phthalocyanine and five parts 0f L12-hydroxy benzoylamino) anthraquinone was dissolved in 92 parts ofl 93% sulfuric acid at lll-.15 C,y When solution. was complete,

the mixture was. drowned'into 400 parts of l'aked ice and 600 parts of Water withvigorous stirring, The precipitated pigment was removed by ltration, washed acid-.free and dried at4 6577i? C.

I he product is a soit, fluffy, green pigment.

formulation the new product showed only a slight break after 103 Fade-Ometer hours while thel Chrome Green had become much bluer..

EXAMPLE 2 EXAMPLE 3 Part A 20 parts of copper phthalocyanine was dissolved in 280 parts of 98% sulfuric acid at 50-55 C. 40 parts of xylene was added to the solution and the mixture stirred until sulfonation of the xylene was complete. drowned into 400 parts of ice and 600 parts of Water with vigorous stirring. The aqueous pigment slurry which resulted was ltered and the cake Washed successively with Water until acidfree, with 500 parts of 1% sodium carbonate, and again with water until alkali-free.

One-half of the product was dried at (i5-70 C. The other half was kept as a Wet paste.

Part B 20 parts of 1-(2-hydroxybenzoylamino) anthraquinone was acid-pasted in 280 parts of 98% sulfuric acid at -15 C. The mixture was worked up as described in Part A.

One-half of the product was dried at 65-70 C. The other half was kept as a Wet paste.

Part C 2.5 parts of dry copper phthalocyanine from Part A and 7.5 parts of dry 1-(2-hydroxybenzoylamino) anthraquinone from Part B were thoroughly blended.

Part D 2.5 parts of copper phthalocyanine (as pulp) from Part A and 7.5 parts of l-(2hydroxyben zoylamino) anthraquinone (as pulp) from Part B were thoroughly blended and the mix dried at 6570 C. The pigments of Parts C and D Were of bright green shade and had properties comparable to the product of Example l.

EXAMPLE 4 5 parts of copper phthalocyanine Was dissolved in 150 parts of conc. H2504 at 50-55 C. The

solution was cooled to -20 C. and 2.5 parts EXAMPLE 5 Example 4 was duplicated using 5 parts oi copper phthalocyanine and 7.5 parts of l-benzoylaminoanthraquinone.

The pigment thus produced is an attractive light-green shade and has properties comparable to the pigment of Example 1.

The mixture was then 6 EXAMPLE e 2.5 parts of copper phthalocyanine was dissolved in 150 parts of conc. H2804 at 50-55 C.' The solution was cooled to 15-20 C. and 2.5 parts of 1-(2chlorobenzoylamino) anthraquinone added. The mixture was Worked up as in Example 4.

The pigment thus produced has an attractive dark-green shade and properties comparable to the pigment of Example 1.

EXAMPLE 7 2.5 parts of copper phthalocyanine and 7.5 parts of the condensation product of isophthalyl chloride and l-aminoanthraquinone Were co-acid pasted by the method described in Example 4. The product Was a bright green pigment of properties comparable to those of the product of Example 1.

EXAMPLE 8 2.5 parts of metal-free phthalocyanine and 7.5 parts of 1-(2-hydroxybenzoylamino) anthraquinone were co-acid pasted according to Example 4, but keeping the temperature at 05 C. The product was a bright green pigment` of properties comparable to those of the product of Example 1.

EXAMPLE 9 2.5 parts of nickel phthalocyanine and 7.5 parts of 1-(2-hydroxybenzoylamino) anthraquinone were co-acid pasted according to Example 4. The product Was a bright green pigment of properties comparable to those of the product of Example 1.

EXAIVIPLE 10 2.5 parts of monochloro copper phthalocyanine and 7.5 parts of 1-(2'hydroxybenzoylamino) anthraquinone were co-acid pasted according to Example 4. The product was a bright green pigment of properties comparable to those of the product of Example l.

EXAMPLE 1 1 5 parts of a highly chlorinated copper phthalocyanine prepared according to Example 1 of U. S. P. 2,247,752 and 7.5 parts of 1-(2-hydroxybenzoylamino) anthraquinone were co-acid pasted according to Example 4. The product was a bright yellow-green pigment of exceptional fastness properties.

We claim:

1. A green pigment composition having as its only essential color constituent a blend of a blue to green phthalocyanine pigment and a yellow alpha aromatic acylamino anthraquinone, the proportions being from 9i) to 33% of the anthraquinone pigment and l0 to 66% of the phthalocyanine pigment.

2. A green pigment composition having as its only essential color constituent a blend of copper phthalocyanine and yellow alpha aromatic acylamino anthraquinone, the proportions being from 9() to 33% of the anthraquinone pigment and 10 to 66% of the phthalocyanine pigment.

3. A green pigment composition having as its only essential color constituent a blend of copper phthalocyanine and l-benzoylamino anthraquinone, the proportions being from to 33% of the anthraquinone pigment and 10 to 66% of the phthalocyanine pigment.

4. A green pigment composition having as its only essential color constituent a blend of copper phthalocyanne and '1\'(flydroxybenzoylamino) enthraquinonethe .proportions being from '90 'to A'331% `of Athe anthraquinorie pigment md 1,0 tol@v of the plritl'ietiocyemine pigmenty "5. Argreen pigment composition having asits 'only essential Icolor constituent a blend of copper p'lithal`oc`yatnine and isopht'halic acid di- (alphaanthraquinonyl) 4timide, the proportions being f'ro'i'nQO to 33% ofthe anthraquinone pigment and I10 -to 66% of thephthalocyanine pigment. 6. A method of prep'ring green pigment blends which comprises aoidpasting a blue to green phthalocyanine pigment and a yellow alpha aromaticv acylamino anthraquinoney and coprecipidating va blend of the pigment with Water, the` proportionsfbeing -from 90 to 33% of the anthra quinonegpigmentand Y10 to 66% of the phthala-YV c-yani-ne pigment.

i7. A method of preparing green pigment blends which comprises acid pasting copper phthalacyanine and a yellow/alpha aromatic acyla-mino anthraquinone, sind coprecipitetingv a: blend "of the pigment With` Water, the proportions being from 90 to 33% of the anthraquinonepigmenteind 10 to66 of the phthalooyanine pigment.

8. A fmethod according to claim 'l in which the 9,- A method -accordingto claim "l in whichl the alpha aromatic eylamino anthrafqninone is 1- (YZ'fnydroXybenzoylamino) antnraquinone.

10. lA'nrietlriodrecording to claim 7 in which the Valpha. aromatic acylamino anthrafqninonenis isophthalic -acid cli-(alpha. anthraquinonyD amide;

RQBERT E. BROUJLLARD.

REFERENCES GITED The following references are of record in the le of this patent:

vUNITED STAT-ES PATENTS 

1. A GREEN PIGMENT COMPOSITION HAVING AS ITS ONLY ESSENTIAL COLOR CONSTITUENT A BLEND A BLUE TO GREEN PHTHALOCYANINE PIGMENT AND A YELLOW ALPHA AROMATIC ACYLAMINO ANTHRAQUINONE, THE PROPORTIONS BEING FROM 90 TO 33% OF THE ANTHRAQUINONE PIGMENT AND 10 TO 66% OF THE PHTHALOCYANINE PIGMENT. 